package com.carouseldemo.main;
/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */



import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import javax.microedition.khronos.opengles.GL10;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLUtils;



/**
 * A vertex shaded cube.
 */
class Cube
{
	/** The buffer holding the vertices */
	private FloatBuffer vertexBuffer;
	/** The buffer holding the texture coordinates */
	private FloatBuffer textureBuffer;
	/** The buffer holding the indices */
	private ByteBuffer indexBuffer;
	
	/** Our texture pointer */
	private int[] textures = new int[1];

	/** 
	 * The initial vertex definition
	 * 
	 * Note that each face is defined, even
	 * if indices are available, because
	 * of the texturing we want to achieve 
	 */	
    private float vertices[] = {
    					//Vertices according to faces
			    		-1.0f, -1.0f, 1.0f, //Vertex 0
			    		1.0f, -1.0f, 1.0f,  //v1
			    		-1.0f, 1.0f, 1.0f,  //v2
			    		1.0f, 1.0f, 1.0f,   //v3
			    		
			    		1.0f, -1.0f, 1.0f,	//...
			    		1.0f, -1.0f, -1.0f,    		
			    		1.0f, 1.0f, 1.0f,
			    		1.0f, 1.0f, -1.0f,
			    		
			    		1.0f, -1.0f, -1.0f,
			    		-1.0f, -1.0f, -1.0f,    		
			    		1.0f, 1.0f, -1.0f,
			    		-1.0f, 1.0f, -1.0f,
			    		
			    		-1.0f, -1.0f, -1.0f,
			    		-1.0f, -1.0f, 1.0f,    		
			    		-1.0f, 1.0f, -1.0f,
			    		-1.0f, 1.0f, 1.0f,
			    		
			    		-1.0f, -1.0f, -1.0f,
			    		1.0f, -1.0f, -1.0f,    		
			    		-1.0f, -1.0f, 1.0f,
			    		1.0f, -1.0f, 1.0f,
			    		
			    		-1.0f, 1.0f, 1.0f,
			    		1.0f, 1.0f, 1.0f,    		
			    		-1.0f, 1.0f, -1.0f,
			    		1.0f, 1.0f, -1.0f,
											};
    
    /** The initial texture coordinates (u, v) */	
    private float texture[] = {    		
			    		//Mapping coordinates for the vertices
			    		0.0f, 0.0f,
			    		0.0f, 1.0f,
			    		1.0f, 0.0f,
			    		1.0f, 1.0f, 
			    		
			    		0.0f, 0.0f,
			    		0.0f, 1.0f,
			    		1.0f, 0.0f,
			    		1.0f, 1.0f,
			    		
			    		0.0f, 0.0f,
			    		0.0f, 1.0f,
			    		1.0f, 0.0f,
			    		1.0f, 1.0f,
			    		
			    		0.0f, 0.0f,
			    		0.0f, 1.0f,
			    		1.0f, 0.0f,
			    		1.0f, 1.0f,
			    		
			    		0.0f, 0.0f,
			    		0.0f, 1.0f,
			    		1.0f, 0.0f,
			    		1.0f, 1.0f,
			    		
			    		0.0f, 0.0f,
			    		0.0f, 1.0f,
			    		1.0f, 0.0f,
			    		1.0f, 1.0f,

			    							};
        
    /** The initial indices definition */	
    private byte indices[] = {
    					//Faces definition
			    		0,1,3, 0,3,2, 			//Face front
			    		4,5,7, 4,7,6, 			//Face right
			    		8,9,11, 8,11,10, 		//... 
			    		12,13,15, 12,15,14, 	
			    		16,17,19, 16,19,18, 	
			    		20,21,23, 20,23,22, 	
    										};

	/**
	 * The Cube constructor.
	 * 
	 * Initiate the buffers.
	 */
	public Cube() {
		//
		ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4);
		byteBuf.order(ByteOrder.nativeOrder());
		vertexBuffer = byteBuf.asFloatBuffer();
		vertexBuffer.put(vertices);
		vertexBuffer.position(0);

		//
		byteBuf = ByteBuffer.allocateDirect(texture.length * 4);
		byteBuf.order(ByteOrder.nativeOrder());
		textureBuffer = byteBuf.asFloatBuffer();
		textureBuffer.put(texture);
		textureBuffer.position(0);

		//
		indexBuffer = ByteBuffer.allocateDirect(indices.length);
		indexBuffer.put(indices);
		indexBuffer.position(0);
	}

	/**
	 * The object own drawing function.
	 * Called from the renderer to redraw this instance
	 * with possible changes in values.
	 * 
	 * @param gl - The GL Context
	 */
	public void draw(GL10 gl) {
		//Bind our only previously generated texture in this case
		gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
		
		//Point to our buffers
		gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
		gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

		//Set the face rotation
		gl.glFrontFace(GL10.GL_CCW);
		
		//Enable the vertex and texture state
		gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
		gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
		
		//Draw the vertices as triangles, based on the Index Buffer information
		gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer);
		
		//Disable the client state before leaving
		gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
		gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
	}
	
	/**
	 * Load the textures
	 * 
	 * @param gl - The GL Context
	 * @param context - The Activity context
	 */
	public void loadGLTexture(GL10 gl, Context context) {
		//Get the texture from the Android resource directory
		InputStream is = context.getResources().openRawResource(R.drawable.nehe);
		Bitmap bitmap = null;
		try {
			//BitmapFactory is an Android graphics utility for images
			bitmap = BitmapFactory.decodeStream(is);

		} finally {
			//Always clear and close
			try {
				is.close();
				is = null;
			} catch (IOException e) {
			}
		}

		//Generate one texture pointer...
		gl.glGenTextures(1, textures, 0);
		//...and bind it to our array
		gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
		
		//Create Nearest Filtered Texture
		gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
		gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);

		//Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE
		gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT);
		gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT);
		
		//Use the Android GLUtils to specify a two-dimensional texture image from our bitmap
		GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
		
		//Clean up
		bitmap.recycle();
	}
}
